Smartcarb SC2 users?
- Thread starter Wbdisco
- Start date
Wbdisco
Member
After the initial install my idle is high and hanging. The performance is snappy to say the least, the idle just stays around 3400rpms. I did try to adjust it down with the idle screw down to about 2400 and it sounds like it?s camming(bouncing up and down 100-200 rpms). I set the idle screw back to factory once I realized I didn?t really help the problem. I also performed a die-off test and bike did a noticeable surge before shutting off. My initial setup is 85 clicks from full rich.
I also noticed that i have to tilt the carb to make sure I have clearance on the case and the chain. I was curious if y?all had the same fitment issues.
The high hanging idle would normally indicate an air leak, but my old carb ran fine. I?ve got an email to Smartcarb also and just waiting to hear back. I like the idea of this carb and I?m hoping it is just user/install error. I did not install a new throttle cable, it seemed fine with free play. I added the fuel filter they provided and put clear fuel line. I will say the fuel line does have bubbles, not sure if that is normal.
Link to the idle video
https://youtu.be/kbNwh984oq4?feature=shared
I also noticed that i have to tilt the carb to make sure I have clearance on the case and the chain. I was curious if y?all had the same fitment issues.
The high hanging idle would normally indicate an air leak, but my old carb ran fine. I?ve got an email to Smartcarb also and just waiting to hear back. I like the idea of this carb and I?m hoping it is just user/install error. I did not install a new throttle cable, it seemed fine with free play. I added the fuel filter they provided and put clear fuel line. I will say the fuel line does have bubbles, not sure if that is normal.
Link to the idle video
https://youtu.be/kbNwh984oq4?feature=shared
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coopernicus
Platinum Level Site Supporter
I've fit a Smartcarb to a 2011, 2014, and a 2018 GG 300. On all of those there was interference for the cases to the float bowl of the carb and it had to be tilted. In doing that, the float height needs to be set lower (in my opinion). I am going to try a carb spacer from an early 90s CR 250 Honda to see if that helps (I think it will).
I would suggest a new cable as the one I tried to use that I already had on the bike did not work. It resulted in a the revving that you experienced as it did not seat properly in the slide. Get the Motion Pro that is 4 inches longer (10-3000 is the part number I ordered). That allowed the cable to seat properly and not get hung up when I turned my bars.
The SC2 that I have on my 2018 300GP has a needle (AQ-07) that is too rich. I have conversed with SC tech support and will go to leaner needle. However, that is my case, for my mods, my style of riding, and at my altitude (my riding typically starts at 7k feet and goes up over 12k feet). Another rider in our group is having the same richness on his needle for similar conditions but with no mods. A third rider in our group has an SC needle that works fine on his 2019 6 Days.
Even with the setup issues, I am fine with the SC. I bought the 2018 used and it had a Lectron on it. It had no power compared to other GG 300s I had and my friends have. That is the knock on the Lectron, no power on the bottom, mid, or top. The SC2 running too rich feels like it has 8 more horsepower.
Good luck and let us know how you make out!
Eric
I would suggest a new cable as the one I tried to use that I already had on the bike did not work. It resulted in a the revving that you experienced as it did not seat properly in the slide. Get the Motion Pro that is 4 inches longer (10-3000 is the part number I ordered). That allowed the cable to seat properly and not get hung up when I turned my bars.
The SC2 that I have on my 2018 300GP has a needle (AQ-07) that is too rich. I have conversed with SC tech support and will go to leaner needle. However, that is my case, for my mods, my style of riding, and at my altitude (my riding typically starts at 7k feet and goes up over 12k feet). Another rider in our group is having the same richness on his needle for similar conditions but with no mods. A third rider in our group has an SC needle that works fine on his 2019 6 Days.
Even with the setup issues, I am fine with the SC. I bought the 2018 used and it had a Lectron on it. It had no power compared to other GG 300s I had and my friends have. That is the knock on the Lectron, no power on the bottom, mid, or top. The SC2 running too rich feels like it has 8 more horsepower.
Good luck and let us know how you make out!
Eric
Wbdisco
Member
I?ll order a throttle cable just to be sure, but I can clearly hear the slide land when I let off the throttle. Also I didn?t have any issues turning lock to lock. The Smartcarb dude got back with me and said the tilting the carb was a GasGas/Rieju deal and shouldn?t affect the carb. Max elevation inside is 2500 feet. I?m gonna do some testing when I get home this evening. I went ahead and ordered another rubber boot between the reeds and carb just to be sure.
The bike rips on the low end now for sure, I?m gonna try some adjustments that Smartcarb suggested and see what happens. I?ll keep yall updated.
The bike rips on the low end now for sure, I?m gonna try some adjustments that Smartcarb suggested and see what happens. I?ll keep yall updated.
Mine had a high idle when I first started the bike.
Gave it a couple miles then turned it down.
I've found that with the S/C, what you think is lean is actually rich.
You just have to play with the metering rod adjustment in either direction..
Just remember where the base line setting is.
Gave it a couple miles then turned it down.
I've found that with the S/C, what you think is lean is actually rich.
You just have to play with the metering rod adjustment in either direction..
Just remember where the base line setting is.
Wbdisco
Member
Here is the idle at stock, plus turning the idle screw. Also turning lock to lock. This is after 10 minutes riding and warmed up.https://youtu.be/NFvO_t1tE80?feature=shared
Smartcarb dude said to go richer two clicks and use idle screw. It had no effect really. Idle dropped 200rpms maybe
Smartcarb dude said to go richer two clicks and use idle screw. It had no effect really. Idle dropped 200rpms maybe
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Wbdisco
Member
That was my suspicion but I?ve double checked the boot, it looks fine. I?ve got one on the way from CPD. I am tempted to take it out and put the old carb back on and start over. Truly the only place that it can be is that boot between the carb and reeds. I never had any issues before so I?m guessing I must have done something on install.
I wouldn't be afraid to turn the idle screw down even more.
I've never got that 2mm throttle slide gap number to work, always lower.
Also, open the throttle slightly ( engine off) when adjusting the idle. Keeps the adjustment screw from digging into the throttle slide.
I've never got that 2mm throttle slide gap number to work, always lower.
Also, open the throttle slightly ( engine off) when adjusting the idle. Keeps the adjustment screw from digging into the throttle slide.
Wbdisco
Member
I?ll give it a try, I did adjust the idle screw way lower but it ran like hell. I realize it?s a a give and take between the metering rod and idle adjustment. I?m just going to take a real close look again this evening, but dang it?s not like I was rebuilding the top end, it?s just a carb swap.
coopernicus
Platinum Level Site Supporter
I know what you mean. The exact same thing happened this past spring when I swapped out my Lectron for the SC2 as the only thing I did on the bike. I figured (wrongly) that the existing cable and throttle tube would work. I installed the SC2, it started fine, rode it up and down the street, and all seemed okay with just a little play in the throttle. I checked for the sound of the slide bottoming and it was a distinct "thunk" sound and I thought it was good for a riding trip the next weekend. Right before I left, I started the bike and it revved really high...I shut it off and traced it to the throttle tube (which apparently was not stock). The cable was binding in the throttle housing as the slack was causing an issue. I rigged it for the ride and I had intermittent revving while I was riding. When I got home, I ordered that new Motion Pro cable and pulled the throttle tube off of my 2014 that I bought from new and knew the throttle tube was stock. When I went to install the new cable, I found the old cable somehow was not secured in the slide properly (the only explanation is that I failed to install it properly or the excess slack allowed it to get sloppy in there). Once I had the new cable installed and a stock throttle tube, it has been perfect ever since.
Wbdisco
Member
Well I have a cable that should be here today, the rubber hopefully tomorrow or Thursday. I?m trying to rule everything out. The throttle cable I?m not sure of, I took it completely off the throttle housing and cam and it didn?t effect anything. Only thing I can do it start from scratch and be more careful, although I feel I was careful from the start.
Wbdisco
Member
Cable came in today, no change. I went ahead and pulled it. I?m gonna start from scratch. My new clamps and rubber boot are on the way so it will give me some time to study a little.
I did notice that the rubber boot does obstruct air/fuel flow, see picture. I will probably port match the new rubber. After porting chainsaws as a hobby I realized that even little things can have big effects. Also, I checked float level and it is a little high with the carb mounted like it is for clearance of the chain and case. I will keep updating as things go, maybe I?ll figure it out and be able to help the next guy.
I did notice that the rubber boot does obstruct air/fuel flow, see picture. I will probably port match the new rubber. After porting chainsaws as a hobby I realized that even little things can have big effects. Also, I checked float level and it is a little high with the carb mounted like it is for clearance of the chain and case. I will keep updating as things go, maybe I?ll figure it out and be able to help the next guy.
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Wbdisco
Member
Keihin is back on, same air boot, same clamps, same fuel line with filter. Heck even had the cable choke. Runs like a sewing machine, smooth and no hanging idle. Here is a vid I filmed.
https://youtube.com/shorts/aIxzkcVN0C8?feature=shared
I will put the SC2 back on when I get my new boot and clamps, although I pretty sure it ain?t the problem.
https://youtube.com/shorts/aIxzkcVN0C8?feature=shared
I will put the SC2 back on when I get my new boot and clamps, although I pretty sure it ain?t the problem.
